An adaptive large neighborhood search algorithm for a selective and periodic inventory routing problem

We study a selective and periodic inventory routing problem (SPIRP) and develop an Adaptive Large Neighborhood Search (ALNS) algorithm for its solution. The problem concerns a biodiesel production facility collecting used vegetable oil from sources, such as restaurants, catering companies and hotels that produce waste vegetable oil in considerable amounts. The facility reuses the collected waste oil as raw material to produce biodiesel. It has to meet certain raw material requirements either from daily collection, or from its inventory, or by purchasing virgin oil. SPIRP involves decisions about which of the present source nodes to include in the collection program, and which periodic (weekly) routing schedule to repeat over an infinite planning horizon. The objective is to minimize the total collection, inventory and purchasing costs while meeting the raw material requirements and operational constraints. A single-commodity flow-based mixed integer linear programming (MILP) model was proposed for this problem in an earlier study. The model was solved with 25 source nodes on a 7-day cyclic planning horizon. In order to tackle larger instances, we develop an ALNS algorithm that is based on a rich neighborhood structure with 11 distinct moves tailored to this problem. We demonstrate the performance of the ALNS, and compare it with the MILP model on test instances containing up to 100 source nodes.     

Electrodeposition of 3D Ordered Macroporous Germanium from Ionic Liquids: A Feasible Method to Make Photonic Crystals with a High Dielectric Constant

A promising method for the production of germanium photonic crystals consists of electrodeposition of Ge from GeCl₄‐containing ionic liquids inside templates of polystyrene colloidal crystals and subsequent removal of the template. This room‐temperature method gives rise to the fabrication of a three‐dimensional highly ordered macroporous germanium nanostructure (see picture; scale: 2 μm) as a prototype of a photonic crystal.

     

Synthesis and anti-bacterial activities of some novel Schiff bases derived from aminophenazone

A series of 1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one-containing Schiff bases were synthesized, characterized and screened for their antibacterial activities. The structures of the synthesized compounds were established by spectroscopic (FT-IR, 1H-NMR, 13C-NMR, MS) and elemental analyses. The anti-bacterial activities (with MIC values) of compounds were evaluated. The anti-bacterial screening results reveal that among the six compounds screened, four compounds showed moderate to good anti-bacterial activity. Among the tested compounds, the most effective compounds against four bacterial strains, viz. Escherichia coli, Staphylococcus aureus, Salmonella typhimurium and Streptococcus pyogenes, are [(2-chlorobenzylidene)amino]-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one (4) and [(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-ylimino)methyl]benzonitrile (5) with MIC values of 6.25 μg/mL.     

Cationic nitrile‐functionalized Ag(I)‐ and Hg(II)‐N‐heterocyclic carbene complexes of CCC,CNC, and NCN pincer‐type carbene ligands: Synthesis,crystal structures,and characterization

Three nitrile‐functionalized (benz)imid‐ zaolium derivatives with CCC, CNC, and NCN coordination pockets have been synthesized and isolated as the bromide salts and are converted into their hexafluorophosphate counterparts ( 5–7 ) by ligand metathesis. N‐heterocyclic carbene Ag(I)‐ and Hg(II)‐complexes ( 8–10 and 11–13 ) are readily formed in good to excellent yields from ligand precursors 5–7 and Ag₂O and Hg(OAc)₂, respectively. All reported compounds have been characterized by various spectral and analytical techniques, such as FTIR, ¹H, and ¹³C NMR spectroscopy and X‐ray diffraction studies. Solid‐state structures of carbene precursors 5 , 7 , and an Ag(I)–carbene complex 10 have been determined crystallographically. Single crystal X‐ray crystallography of complex 10 reveals the chelation of carbene carbons to metal center in almost a linear manner. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 23:486–497, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21041     

Tate twists of Hodge structures arising from abelian varieties of type IV

We show that certain abelian varieties $A$ have the property that for every Hodge structure $V$ in the cohomology of $A$, every effective Tate twist of $V$ occurs in the cohomology of some abelian variety. We deduce the general Hodge conjecture for certain non-simple abelian varieties of type IV.     

Near-surface structural phase transition of SrTiO3 studied with zero-field beta-detected nuclear spin relaxation and resonance

We demonstrate that zero-field beta-detected nuclear quadrupole resonance and spin relaxation of low energy (8)Li can be used as a sensitive local probe of structural phase transitions near a surface. We find that the transition near the surface of a SrTiO(3) single crystal occurs at T(c) approximately 150K, i.e., approximately 45K higher than T(c)bulk, and that the tetragonal domains formed below T(c) are randomly oriented.     

Analysis of heat conduction in a disk brake system

In this paper, the governing heat equations for the disk and the pad are extracted in the form of transient heat equations with heat generation that is dependant to time and space. In the derivation of the heat equations, parameters such as the duration of braking, vehicle velocity, geometries and the dimensions of the brake components, materials of the disk brake rotor and the pad and contact pressure distribution have been taken into account. The problem is solved analytically using Green’s function approach. It is concluded that the heat generated due to friction between the disk and the pad should be ideally dissipated to the environment to avoid decreasing the friction coefficient between the disk and the pad and to avoid the temperature rise of various brake components and brake fluid vaporization due to excessive heating.     

Molecular Complexes of Crown Ethers: Part 8. Effect of Surfactant on the Charge Transfer Complexes of 18C6 with Picric Acid in the Presence of Alkali Metal Ions

The interaction of 18-crown-6 (CE) with picric acid(PA) was studied in the UV-Visible region in 1,2-dichloroethane (DCE) at 298.2 K. The effect of the surfactant Triton X-100 was studied, and it was found to have a pronounced effect on the interaction of 18-crown-6 with picric acid. The effect of the alkali metal cations, especially Na and K on the complex matrix donor–acceptor surfactant was studied. It is found that the extraction of the insoluble solid NaCl and KCl to the organic phase increased by more than 8-fold in the presence of the complex. The interaction of the alkali metals ions, i.e., Li, Na, K, Cs and Rb with the systems Donor–Acceptor and Donor–Acceptor–Triton were studied. It is found that the stability of the complexes formed between the system CE + Triton + Picric acid and the alkali metals ions depends on the ratio between the crown ether radius and the alkali metal radius.     

Copper‐Catalyzed Dehydrogenative Cross‐Coupling Reaction between Allylic CH Bonds and α‐CH Bonds of Ketones or Aldehydes

A dehydrogenative cross‐coupling reaction between allylic C?H bonds and the α‐C?H bond of ketones or aldehydes was developed using Cu(OTf)₂ as a catalyst and DDQ as an oxidant. This synthetic approach to γ,δ‐unsaturated ketones and aldehydes has the advantages of broad scope for both ketones and aldehydes as reactants, mild reaction conditions, good yields and atom economy. A plausible mechanism using Cu(OTf)₂ as a Lewis acid catalyst was also proposed (DDQ=2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone; Tf=trifluoromethanesulfonate).